Hey, On 03/06/2016 05:28 AM, Adam Hunt wrote: > With all the chatter about the CI situation lately I got to wondering if > there might be some way I could help out. It sound like Kaspar has > things under control with the new CI system but what about builders; are > there enough CPU cycles available for the current rate of RIOT > development, what about future development?
For now, it's a *huge* improvement over travis. As dipswitch already wrote, build times depend a lot on cache hits. A change somewhere outside of core can take less than 6 minutes to build, a change to a core header like thread.h basically forces a full cold-cache rebuild, taking >30 minutes. Also, a build that is mostly cache-miss fills the ccache (currently set at 150gb), and ccache has a weird pruning strategy, as the cache fill rate goes close to 150g, then drops to <50gb, probably pruning more than necessary. Not using ccache at all takes ~22 minutes, so I'm considering either not using ccache, or disabling it when certain conditions apply, like a diff in core/include. I think there's quite a bit room for improvement apart from that: - the cached builds are SSD IO bound, averaging > 5k transactions per sec, reading >100MB/s while writing ~20MB/s. Putting the whole cache in memory seems expensive (anyone has spare 256gb in DDR3 DIMMS?), but a RAID0 of SSD's would probably speed up things. - the current build system is horribly inefficient. While that doesn't matter for builds of one app for one MCU, when building all ~4000 combinations, it matters. Like, all RIOT's source files get stat'ed 4k times, every compiler check gets called 4k times, every "(shell ls blah)", ....... I'm working on an improved build system, but it'll be a while until it is production ready, if we even decide to step away from make - less drastic would be a rewrite of compile_test.py + "buildtest" make target, as that is not parallizing very well. This is also needed for properly distributing the builds, as with the current scripts, the smallest "chunk" is basically one MCU group, which on a quad core box probably takes as much time to build as the worst case 22minutes. > Would it be possible for me and/or other members of the community to > donate CPU time for use as builders? Sure, as soon as we can make use of it! > If CI builders could be deployed as VMs, or better yet, Docker images > (lighter weight) would it be possible for people like me to help > out? I agree, Docker is the way to go here. Kaspar _______________________________________________ devel mailing list devel@riot-os.org https://lists.riot-os.org/mailman/listinfo/devel
